Significant figures and scientific notations
This presentation is the property of its rightful owner.
Sponsored Links
1 / 11

Significant Figures and Scientific Notations PowerPoint PPT Presentation


  • 72 Views
  • Uploaded on
  • Presentation posted in: General

Significant Figures and Scientific Notations. Examples and Problems. Rules for Counting Significant Figures. 1. Nonzero integers always count as significant figures. 2. Zeros: There are three classes of zeroes. Leading zeroes precede all the nonzero digits and DO NOT count as

Download Presentation

Significant Figures and Scientific Notations

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Significant Figures and Scientific Notations

Examples and Problems


Rules for Counting Significant Figures

1. Nonzero integers always count as significant figures.

2. Zeros: There are three classes of zeroes.

  • Leading zeroes precede all the nonzero digits and DO NOT count as

  • significant figures. Example: 0.0025 has ____ significant figures.

  • Captive zeroes are zeroes between nonzero numbers. These always

  • count as significant figures. Example: 1.008 has ____ significant figures.

  • Trailing zeroes are zeroes at the right end of the number.

  • Trailing zeroes are only significant if the number contains a decimal point.

  • Example: 1.00 x 102 has ____ significant figures.

  • Trailing zeroes are not significant if the number does not contain a decimal

  • point. Example: 100 has ____ significant figure.

  • Exact numbers, which can arise from counting or definitions such as 1 in

  • = 2.54 cm, never limit the number of significant figures in a calculation.

2

4

3

1

Ohn-Sabatello, Morlan, Knoespel, Fast Track to a 5 Preparing for the AP Chemistry Examination2006, page 53


Significant figures: Rules for zeros

Leading zeros are not significant.

Leading zero

– three significant figures

0.421

Captive zeros are significant.

Captive zero

4012

– four significant figures

Trailing zeros are significant.

Trailing zero

114.20

– five significant figures


Significant Figures

  • Counting Sig Figs

    • Count all numbers EXCEPT:

      • Leading zeros -- 0.0025

      • Trailing zeros without a decimal point -- 2,500

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


3 SF

Significant Figures

  • Calculating with Sig Figs

    • Multiply/Divide - The # with the fewest sig figs determines the # of sig figs in the answer.

(13.91g/cm3)(23.3cm3) = 324.103g

4 SF

3 SF

324g

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


Significant Figures

  • Calculating with Sig Figs (con’t)

    • Add/Subtract - The # with the lowest decimal value determines the place of the last sig fig in the answer.

224 g

+ 130 g

354 g

224 g

+ 130 g

354 g

3.75 mL

+ 4.1 mL

7.85 mL

3.75 mL

+ 4.1 mL

7.85 mL

 350 g

 7.9 mL

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


Significant Figures

  • Calculating with Sig Figs (con’t)

    • Exact Numbers do not limit the # of sig figs in the answer.

      • Counting numbers: 12 students

      • Exact conversions: 1 m = 100 cm

      • “1” in any conversion: 1 in = 2.54 cm

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


1. (15.30 g) ÷ (6.4 mL)

 2.4 g/mL

2 SF

Significant Figures

Practice Problems

4 SF

2 SF

= 2.390625 g/mL

2. 18.9g

- 0.84 g

 18.1 g

18.06 g

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


Scientific Notation

65,000 kg  6.5 × 104 kg

  • Converting into scientific notation:

    • Move decimal until there’s 1 digit to its left. Places moved = exponent.

    • Large # (>1)  positive exponentSmall # (<1)  negative exponent

    • Only include sig. figs.

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


3. 2,400,000 g

4. 0.00256 kg

5. 7  10-5 km

6.6.2  104 mm

Scientific Notation

Practice Problems

2.4  106 g

2.56  10-3 kg

0.00007 km

62,000 mm

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


EXE

EXP

EXP

ENTER

EE

EE

Scientific Notation

  • Calculating with scientific notation

(5.44 × 107 g) ÷ (8.1 × 104 mol) =

Type on your calculator:

5.44

7

8.1

4

÷

= 671.6049383

= 670 g/mol

= 6.7 × 102 g/mol

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem


  • Login